Mozart: Generalize frame scheduling.

mojo/services/gfx/composition/interfaces/scenes.mojom

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [DartPackage="mojo_services"]
 module mojo.gfx.composition;
 
 import "mojo/services/gfx/composition/interfaces/nodes.mojom";
 import "mojo/services/gfx/composition/interfaces/resources.mojom";
 import "mojo/services/gfx/composition/interfaces/scene_token.mojom";
@@ skipping 99 matching lines @@
 //   B's old content.
 //
 // - Speculate: The compositor could allow X to provide alternate descriptions
 //   of the scene in the case where A or B are not keeping up so that it
 //   can more finely control the recovery policy.
 //
 // To maximize concurrency, we adopt the latter approach.
 //
 // SCHEDULING
 //
-// The scene provides support for scheduling update via its associated
-// |SceneScheduler| interface.  Use the scheduler to obtain frame timing
+// The scene provides support for scheduling frames via its associated
+// |FrameScheduler| interface.  Use the scheduler to obtain frame timing
 // information and to throttle updates to match the display refresh rate
 // (ie. with vsync).
 interface Scene {
   // Sets the listener for receiving events from the scene.
   //
   // If |listener| is null, then the previously set listener is removed.
   SetListener(SceneListener? listener);
 
   // Applies a batch of incremental updates to the contents of the scene.
   //
@@ skipping 16 matching lines @@
   // The |metadata| describes how the published scene should be presented.
   // If null, this method behaves as if a |SceneMetadata| object initialized
   // with default values had been supplied.
   //
   // Publishing a scene graph applies all pending updates.  It is an error
   // to publish updates which cause the scene state to become inconsistent,
   // such as by having nodes which refer to non-existent resources or
   // introducing cycles in the scene's nodes; the connection will be closed.
   Publish(SceneMetadata? metadata);
 
-  // Gets a scheduler for scheduling upcoming scene operations.
-  GetScheduler(SceneScheduler& scheduler);
+  // Gets a scheduler to receive frame timing information for the scene.
+  GetScheduler(FrameScheduler& scheduler);
 };
 
 // An interface applications may implement to receive events from a scene.
 interface SceneListener {
   // Called when a resource has become unavailable.
   //
   // Any nodes which are using the resource will be considered blocked
   // until the resource is replaced or the nodes using it are removed.
   OnResourceUnavailable(uint32 resource_id) => ();
 };
@@ skipping 45 matching lines @@
   // scene are to be shown on the display output assuming everything is
   // fully rendered and submitted by the appropriate deadline.
   //
   // Expressed in microseconds in the |MojoTimeTicks| timebase.
   //
   // A value of 0 means "as soon as possible".
   //
   // See also: |FrameInfo.presentation_time|.
   int64 presentation_time = 0;
 };